Process of coating cotton yarn



April 19, 1955 L. DENISTON 2,706,596

PROCESS OF comma COTTON YARN Filed Aug. 14, 1951 I/Ill/l/ l l llll][flll INVENTOR GEORGE L.DENISTON BY 67 ATTORNEYS United States Patent PROCESS OF COATING COTTON YARN George L. Deniston, Dayton, Ohio, assignor to The Commonwealth Engineering Company of Ohio, Dayton, Ohio, a corporation of Ohio Application August 14, 1951, Serial No. 241,740

11 Claims. (Cl. 1177) This invention relates to a process of treating cotton threads, yarns and fabrics with dextran and its derivatives and to the products produced thereby.

Dextran is a water soluble colloidal material produced by the action of micro-organisms on sucrose bearing materials and may be converted into dextran ethers and esters as described in U. S. Patents 2,344,179, 2,203,702 and 2,385,553.

This invention contemplates the provision of a novel process for the impregnation and coating of cotton materials with dextran and its derivatives.

The invention contemplates the provision of a new product wherein cotton provides a strength core and material impregnated therein and coated thereon provides an outer shell resistant to ordinary chemical attack but which may be rendered sufiiciently tacky by selected solvents for the securing of good adhesions in many materials of commerce.

More particularly, in the process of invention cotton in the form of a thread, yarn or fabric is treated with dextran, dissolved in a solvent, to secure penetration of the dextran into the fibers, and thereafter the dextran bearing cotton is treated with an alkylating agent in an alkaline solution and then subjected to a heating step to form a product resistant to chemical action but selectively attacked by particular solvents. An additional feature of the process, particularly as related to commercial yarn and fabrics as used in rubber and plastic industries, is the substantial elimination of residual stretch therefrom by the heating of the composite body under tensive conditions.

While I prefer to use a combination of sodium hydroxide and water as the dextran solvent, due to the efficiency of this combination in the effecting of a swelling of the cotton fibers to thereby permit maximum penetration of the dextran, other solvents, e. g. water alone, water and sodium carbonate, a dilute acetic acid solution or dilute solutions of the mineral acids such as HCl and H2804 may suitably be employed.

The alkylating agent for the dextran, which is utilized to substitute or add an alkyl group into the dextran, may include: the organic halides such as methyl, ehyl, propyl; isopropyl or benzyl halides; the alkyl sulphates such as diethyl sulphate; tri-ethyl phosphate; and aryl sulfomc alkyl esters such as the ethyl ester of p-toluene sulfonic acid.

The alkylating agent is employed in alkaline solution and this alkali is preferably sodium or potassium hydroxide, sodium carbonate or an organic alkali.

The product of the process of invention may comprise, for example, a destretched yarn having the cotton core surrounded by the benzyl ether of dextran which is insoluble in and substantially unaffected by H2O, alkalis, mineral acids, and the lower aliphatic alcohols, but which when treated with acetone, dioxane, benzene or toluene becomes tacky. Thus this destretched yarn has a particular utility in power transmission belt structures where it may be laminated with rubber and cured thereto. Similarly a fabric treated by the process of invention attains qualities suitable for lamination with resinous materials.

The invention will be more fully understood by reference to the following specific examples and the drawing wherein:

Figure 1 illustrates the apparatus used in the process of invention;

Figure 2 is a view of the grooved roller in Figure l;

Figure 3 is a partial plan view of the apparatus of Figure 1; and

Figure 4 is a plan view of the grooved tapered roller shown in the oven of Figure 1.

Example I There is shown in Figure 1 a tank or vat 1 containing a dextran solution 2, the solution containing by weight approximately 40% dextran of any molecular weight, 55% water and about 5% of sodium hydroxide. A cotton yarn 3 is shown passing continuously from bobbin 4, mounted on roll 5, into the solution 2 where it is guided between rolls 6 and 7, which are adapted to be driven independently by means not shown at speeds differing by about 30%, the roll 7 having the greater velocity. The rolls 6 and 7 are multi-grooved as shown in Figure 2 in order that the timeof passage of the yarn through the solution may be readily controlled, by utilization of a selected number of grooves for particular size yarns.

The yarn is shown in Figure 1 as passing from solution 2 over roll 8 into bath 9 containing alkaline aralkyl halide solution 10 having by weight aproximately 30% of benzyl chloride, 9% of sodium hydroxide and 61% water. The wetted and impregnated yarn 3 passes over rolls 20 and 21 which are grooved similarly to rolls 6 and 7 and after a multipass through the solution, as more clearly seen in Figure 3, enters a heated oven 12 over roller 11. A hollow conical die 13 is positioned between bath 9 and oven 12 to remove any excess material present on the yarn before it passes to the heating operation.

The oven 12 is provided with grooved rollers 14, 15, roller 15 being driven at a speed about 30% in excess of that of roller 14, and the roller 15 having grooves of progressively (Figure 4) increasing diameter, from end 16 to end 17, to facilitate the destretching of the yarn. After curing the yarn is wound up on coil 18 mounted on stand 19.

When impregnating and coating the yarn is passed through bath 2 under tension if desired although the same is not necessary but does assist in the ultimate destretching of the yarn and the dextran pick up is somewhat greater if tension is employed. In solution 10 the dextran and aralkyl halide initiate a reaction which is completed in oven heater 12 at temperatures of about to C.

The finished product has substantially no stretch retained therein and due to the coating resists moisture thus preventing shrinkage effects from occurring in the yarn rendering the product particularly useful where constant yarn length under varying humidity conditions is essential. Since the product is also resistant to alcohols, the mineral acids, and alkalis, it may be employed under conditions where such resistance is beneficial.

It Will be clear from the foregoing that the degree of impregnation of the yarn may be controlled by controlling the solution concentrations particularly the dextran. Furthermore a coating may be applied over the yarn to completely sheath the same by utilizing viscous solution.

Example II contain:

50% dextran 40% water 10% sodium hydroxide The fixing solution may contain:

50% di-ethyl sulphate 30% water 20% sodium hydroxide The procedure is essentially the same as set forth in Example I, the heating temperature however being of the order of l00-115 C.

It will be understood that while there have been given herein certain specific examples of the practice of this invention, it is not intended thereby to have this invention limited to or circumscribed by the specific details of materials, proportions or conditions herein specified, in view of the fact that this invention may be modified according to individual preference or conditions without necessarily departing from the spirit of this disclosure and the scope of the appended claims.

I claim:

1. A process of producing a coated cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn in a dextran solution to impregnate the yarn with dextran, alkylating in an alkaline solution the dextran impregnated in the yarn, and heating the yarn containing the alkylated dextran at a temperature of 100 C. to 140 C. to complete the reaction between the dextran and the alkylating agent.

2. A process of producing a coated cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn in a dextran solution to impregnate the yarn with dextran, alkylating in an alkaline solution the dextran impregnated in the yarn, and heating the yarn containing the alkylated dextran under tension, at a temperature of 100 C. to 140 C. to complete the reaction between the alkylating agent and the dextran and set the yarn in the condition resulting from the application of the tension thereto.

3. A process of producing a coated cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn in a dextran solution containing sodium hydroxide and water to impregnate the yarn with dextran, alkylating in an alkaline solution the dextran impregnated in the yarn, and heating the yarn containing the alkylated dextran under tension, at a temperature of 100 C. to 140 C. to complete the reaction between the alkylating agent and the dextran and set the yarn in the condition resulting from the application of the tension thereto.

4. A process of producing a coated cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn in an aqueous dextran solution to impregnate the yarn with dextran, alkylating in an alkaline solution the dextran impregnated in the yarn, and heating the yarn containing the alkylated dextran under tension, at a temperature of 100 C. to 140 C. to complete the reaction between the dextran and the alkylating agent and set the yarn in the condition resulting from the application of the tension thereto.

5. A process of producing a coated cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn in a dextran solution containing sodium hydroxide and water to impregnate the yarn with dextran, treating the dextran impregnated in the yarn with an aqueous alkaline solution of a sufiicient amount of an alkyl halide to produce an alkylated dextran by reaction of the alkyl halide with the dextran carried by the yarn, and heating the yarn containing the alkylated dextran under tension, at a temperature of 100 C. to 140 C. to complete the reaction between the alkyl halide and the dextran and set the yarn in the condition resulting from the application of the tension thereto.

6. A process of producing a coated cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn in a dextran solution containing sodium hydroxide and water to impregnate the yarn with dextran, treating the dextran impregnated in the yarn with an aqueous alkaline solution of a sufiicient amount of benzyl chloride to produce a benzyl ether of dextran, and heating the yarn containing the benzylated dextran at temperatures in the range of 130 to 140 C. to complete the reaction between the benzyl chloride and the dextran.

7. A process of producing a coated cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn in a dextran solution to impregnate the yarn with dextran, treating the dextran impregnated in the yarn with an aqueous alkaline solution of a sufiicient amount of diethyl sulphate to produce an ethyl ether of dextran, and heating the yarn at temperatures in the range of to C. to complete the reation between the diethyl sulphate and dextran.

8. A process of producing a coated cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn in a dextran solution to impregnate the yarn with dextran, treating the dextran impregnated in the yarn with an aqueous alkaline solution of a sufiicient amount of aralkyl halide to produce an aralkylated dextran, and heating the yarn at temperatures in the range of 100 to 115 C. to complete the reaction between the aralkyl halide and the dextran.

9. A process of producing a coated cotton yarn of high Water and chemical resistance comprising the steps of immersing the yarn in a dextran solution to impregnate the yarn with dextran, treating the dextran impregnated in the yarn with a solution of diethyl sulphate in water and sodium hydroxide containing an amount of diethyl sulphate sufficient to produce an ethyl ether of dextran, and heating the yarn at temperatures in the range of 100 to 115 C. under tension, to complete the reaction between the diethyl sulphate and the dextran and set the yarn in the condition resulting from the application of the tension thereto.

10. A process of producing a coated, destretched cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn under tension in a dextran solution to impregnate the yarn with dextran, alkylating in an alkaline solution the dextran impregnated in the yarn, and heating the impregnated yarn at a temperature in excess of 100 C. and under tension, to complete the reaction between the alkylating agent and the dextran and set the yarn in the condition resulting from the application of the tension thereto.

11. A process of producing a coated, destretched cotton yarn of high water and chemical resistance comprising the steps of immersing the yarn under tension in a dextran solution to impregnate the yarn with dextran, alkylating in an alkaline solution the dextran impregnated in the yarn, removing excess alkylated dextran from the yarn by passing the treated yarn through a conical die, and heating the impregnated yarn at a temperature in excess of 100 C. and under tension, to complete the reaction between the alkylating agent and the dextran and set the yarn in the condition resulting from the application of the tension thereto.

References Cited in the file of this patent UNITED STATES PATENTS 2,203,704 Stahly et al. (1) June 11, 1940 2,203,705 Stahly et al. (2) June 11, 1940 2,352,707 Goldthwait July 4, 1944 2,330,253 Whitehead Sept. 28, 1943 2,336,265 Lester Dec. 7, 1943 2,385,553 Stahly et al. Sept. 25, 1945 2,466,808 Henning et al Apr. 12, 1949 2,503,624 Luaces Apr. 11, 1950 2,542,819 Kropa Feb. 20, 1951 

10. A PRICESS OF PRODUCTION A COATED, DESTRETCHED COTTON YARN OF HIGH WATER AND CHEMICAL RESISTANCE COMPRISING THE STEPS OF IMMERSING THE YARN UNDER TENSION IN A DEXTRAN IN AN ALKALINE SOLUTION THE DEXTRAN INPREGNATED IN THE YARN, AND HEATING THE IMPREGNATED YARN AT A TEMPERATURE IN EXCESS OF 100* C. AND UNDER TENSION, TO COMPLETE THE REACTION BETWEEN THE ALKYLATING AGENT AND THE DEXTRAN AND SET THE YARN IN THE CONDITION RESULTING FROM THE APPLICATION OF THE TENSION THERETO. 